| AVS 55th International Symposium & Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI-WeA |
| Session: | Quantitative Analysis of Biointerfaces |
| Presenter: | M. Edvardsson, Chalmers University of Technology, Sweden |
| Authors: | M. Edvardsson, Chalmers University of Technology, Sweden S. Svedhem, Chalmers University of Technology, Sweden G. Wang, Chalmers University of Technology and Q-Sense AB, Sweden R. Richter, CIC biomaGUNE, Spain M. Rodahl, Q-Sense AB, Sweden B. Kasemo, Chalmers University of Technology, Sweden |
| Correspondent: | Click to Email |
In the past decade, the Quartz Crystal Microbalance with Dissipation monitoring technique (QCM-D) has emerged as a powerful biosensor technique.1 A key feature of the technique is that the shift of the resonant frequency, Δf, obtained upon adsorption of mass on the QCM-D sensor surface includes both the actual mass and solvent (e.g. water) associated with it. For a rigid film containing no water (low dissipation shifts, ΔD), the frequency shift, Δf, can be considered proportional to the mass of the film. For viscoelastic films containing water (high dissipation shifts), however, it is difficult to determine how much of the frequency shift results from the actual adsorbed mass and how much is a contribution from entrapped or associated water. In some applications, the signal enhancement that is obtained through the associated liquid, makes the QCM-D technique unique with respect to the added information that is gained compared to, for example, optical techniques. In particular, spontaneous fusion of lipid vesicles onto solid supports have been studied extensively using the QCM-D technique,2 and unique new information has been obtained. However, for a full picture one would, for such complex viscoelastic films, ideally combine the QCM-D technique with a technique that allows separation of the adsorbed (non-hydrated or “dry”) mass and the associated liquid (wet mass). This presentation demonstrates applications of a recently developed instrument, combining, on the same sensor surface, the QCM-D technique and optical reflectometry [Wang et al., submitted to Rev. Sci Instr,], for surface based analysis of biomolecular and polymer adlayers. The combination instrument makes it possible to do simultaneous, time-resolved measurements of hydrated and non-hydrated mass and viscoelastic properties of films and molecular adlayers formed on the surface. The experimental setup is described, and the value of this combination of techniques is demonstrated via applications on model systems that involve supported lipid structures of various degree of hydration; ranging from systems of low water content, e.g., bilayers, to those of high water content, such as surface-attached vesicles and bilayers with a highly hydrated peptide coupled to it.
1Cooper, M. A.; Singleton, V. T. J. Mol. Rec. 2007, 20, 154-184.
2Richter, R. P.; Bérat, R.; Brisson, A. Langmuir 2006, 22, 3497-3505.